Floor Joist Layout Plan

Designing the framing system for engineered lumber is a little different from dimensional lumber.

Floor joist layout plan.

The widest span in the floor joist span table in part 2 of this tutorial module showed that floor joists can span 17 2 if they are 2 x 12s spaced 12 o c. The dimensional stability of tji joists help them resist warping twisting and shrinking that can lead to squeaky floors. A design value table shows that the joists have an fb value of 1 495 and an e value of 1 900 000. Wooden i joists provide a good balance of strength cost and ease of installation and they are what we are using for the floor joists on the fhb house with lvls for beams and headers.

Use a design value table to find the fb value for your floor joists. Let s expand our house beyond that 17 2 span capability to 24 feet wide. Trus joist tji joists are a key part of making a high performance floor. Some newer homes have manufactured i beam shaped joists.

1 grade 2 by 6 douglas fir larch joists spaced 16 inches on center. On this deck we wanted the layout to begin from the outside of the rim joist that hadn t been installed yet. The easiest way to pull layout is simply to hook the tape on the end of the ledger board and mark a crow s foot every 16 in. Start the layout from a logical point.

Floor joists are typically 2 by 8s 2 by 10s or 2 by 12s. Nine joists will be needed for the 16 foot width. This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction. So the house dimensions will now be 24 x 13.

Draw up a basic floor framing plan. Ceiling joists are usually 2 by 6s or sometimes 2 by 4s if it is an older home. Extremely long spans staircases or interior walls typically require additional support which can complicate your framing. True floor joist span calculations can only be made by a structural engineer or contractor.

I prefer to double the outside joists as do some deck builders which adds 2 joists for a total of 11. Your sketch should depict the floor s basic shape and layout complete with any additional features like alcoves nooks and staircases. A floor s framework is made up mostly of wooden joists that run parallel to one another at regular intervals. Don t worry you won t need to do a lot of calculations in determining the size and placement of the structural framing within your house design.

Using floor joist span tables. Continuing on from part 1. But i ve based the layouts and cost calculations in this article on the minimum number needed according to strucalc this system has a 20 safety margin at a 50 psf load. Tji joists are lightweight and come in long lengths which makes them faster and easier to install than traditional framing and saves you both.

Design information for tji 110 560 joists.